Abstract
Two cDNAs encoding acyl-CoA Z9-desaturase from the fat body and Z10-desaturase from the pheromone gland of the greenheaded leafroller moth, Planotortrix octo, were obtained by RACE PCR. The Z9-desaturase (Pocto-Z9) cDNA spans 2291 nt with an ORF encoding a 352 amino-acid protein, which has 63.1% identity with Trichoplusia ni Z9 desaturase (Tni-Z9). The Z10-desaturase (Pocto-Z10) cDNA spans 2777 nt with an ORF encoding a protein with 356 amino acids. Pocto-Z10 shows a lower identity of amino acids with Pocto-Z9 and Tni-Z9 (47.9% and 45.7% respectively) than that with the Z11 desaturases of T. ni and H. zea (57.4% and 55.7%, respectively). The ORFs of the two P. octo cDNAs were constructed into an expression vector, YEpOLEX, that complemented the unsaturated fatty acid (UFA) auxotrophy of a desaturase-deficient ole1 strain of Saccharomyces cerevisiae. Expression of Pocto-Z9 produced a 4:1 ratio of Z9-16 and Z9-18 acids, with minor amounts (2%) of Z9-14, Z9-15, and Z9-17 acids. Expression of Pocto-Z10 confirmed the regio- and stereo-selectivity of this unusual Z10 desaturase.
Keywords: Z9- desaturase; Z10-desaturase; Planotortrix octo; RT-PCR; cDNA cloning; functional expression, YEpOLEX
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